Treviri: MRA-DEU-Tre001

Augusta Treverorum was established near the turn of the modern era (ca. 16 BC) and came to occupy an important political position in Belgic Gaul. By the 4^th century AD it possessed one of the largest populations of all cities in the Roman Empire. Extant architectural heritage dating to the late Roman period include the Black Gate and the remains of a residence of the Western Roman Emperor. The Black Gate (also known by its Latin name, Porta Nigra) is the largest such structure from the Roman era north of the Alps and is currently recognized as a UNESCO World Heritage Site. In the subsequent centuries, with the decline and fall of the Roman empire, the city lost some of it is standing, but retained important industrial functions.

Sources:

https://en.wikipedia.org/wiki/Porta_Nigra

https://en.wikipedia.org/wiki/Trier

Further reading:

Binsfeld, A. (2013). Augusta Treverorum (Trier). The Encyclopedia of Ancient History.

Drinkwater, J. F. (2015). Augusta Treverorum. In Oxford Research Encyclopedia of Classics.